﻿using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Media;  

namespace BYS.XiAnComDept.App
{
    public static class DataGridExtension
    {
        /// <summary>  
        /// 获取DataGrid控件单元格  
        /// </summary>  
        /// <param name="dataGrid">DataGrid控件</param>  
        /// <param name="rowIndex">单元格所在的行号</param>  
        /// <param name="columnIndex">单元格所在的列号</param>  
        /// <returns>指定的单元格</returns>  
        public static DataGridCell GetCell(this DataGrid dataGrid, int rowIndex, int columnIndex)          
        {  
            DataGridRow rowContainer = dataGrid.GetRow(rowIndex);  
            if (rowContainer != null)  
            {  
                DataGridCellsPresenter presenter = GetVisualChild<DataGridCellsPresenter>(rowContainer);  
                DataGridCell cell = (DataGridCell)presenter.ItemContainerGenerator.ContainerFromIndex(columnIndex);  
                if (cell == null)  
                {  
                    dataGrid.ScrollIntoView(rowContainer, dataGrid.Columns[columnIndex]);  
                    cell = (DataGridCell)presenter.ItemContainerGenerator.ContainerFromIndex(columnIndex);  
                }  
                return cell;  
            }  
            return null;  
        }  
  
        /// <summary>  
        /// 获取DataGrid的行  
        /// </summary>  
        /// <param name="dataGrid">DataGrid控件</param>  
        /// <param name="rowIndex">DataGrid行号</param>  
        /// <returns>指定的行号</returns>  
        public static DataGridRow GetRow(this DataGrid dataGrid, int rowIndex)          
        {  
            DataGridRow rowContainer = (DataGridRow)dataGrid.ItemContainerGenerator.ContainerFromIndex(rowIndex);  
            if (rowContainer == null)  
            {  
                dataGrid.UpdateLayout();  
                dataGrid.ScrollIntoView(dataGrid.Items[rowIndex]);  
                rowContainer = (DataGridRow)dataGrid.ItemContainerGenerator.ContainerFromIndex(rowIndex);  
            }  
            return rowContainer;  
        }  
  
        /// <summary>  
        /// 获取父可视对象中第一个指定类型的子可视对象  
        /// </summary>  
        /// <typeparam name="T">可视对象类型</typeparam>  
        /// <param name="parent">父可视对象</param>  
        /// <returns>第一个指定类型的子可视对象</returns>  
        public static T GetVisualChild<T>(Visual parent) where T : Visual  
        {  
            T child = default(T);  
            int numVisuals = VisualTreeHelper.GetChildrenCount(parent);  
            for (int i = 0; i < numVisuals; i++)  
            {  
                Visual v = (Visual)VisualTreeHelper.GetChild(parent, i);  
                child = v as T;  
                if (child == null)  
                {  
                    child = GetVisualChild<T>(v);  
                }  
                if (child != null)  
                {  
                    break;  
                }  
            }  
            return child;  
        }  
    }
}
